S Slewa-Younan, S van den Berg, I J Baguley, et al. Towards an understanding of sex differences in functional outcome following moderate to severe traumatic brain injury: a systematic review. J Neurol Neurosurg Psychiatry 2008;79:1197–1201. As a result of printer error the first line of the paper was omitted. The first sentence should read: “An important factor mediating the incidence of traumatic brain injury (TBI) is a patient’s sex.”